1. Thoughts on Energy Reach
Arne Freyberger
Operations Department
Accelerator Division
2017 Ops StayTreat

2. Welcome to StayTreat #4!!!
Energy Reach has been a major component of previous StayTreats.

3. 2017 Operation StayTreat OPS DIR Facilities SRF External(SLAC) DOE
Elec. ENG
CASA
CRYO

4. CEBAF System Availability
Weekly availability reviews at the weekly scheduling meeting
Early identification of issues
Monthly availability report
Presented and discussed on the first Friday of a new month at the daily 8am meeting
Look for trends
Increased statistics for better information
Annual availability review is used to set priority for support groups annual work plan (AWP).
Feb shown
A good month
FSD Trip rate: 91.7 % Availability
RF System: 95.4% Availability
FSD*RF = 87.4%
If Availability goal is 70%, the other 14 system must have an Availability > 80%
Every other system must be > 0.8^(1/14) = 98%
Energy Reach is more than integrated gradient, system availability at the chosen gradient is IMPORTANT!!

5. RF MTBF: about two events per day MTTR: low, less than 1h
Would better training of operators improve MTTR even more? Improved controls?

6. Vacuum
Dominated by SRF window failure in Nov 2017

7. CEBAF Performance Plan
Define the performance goals
Availability/Reliability
Beam Parameters (emittance, energy spread, bunch charge, beam energy)
Peak Conditions (Hall multiplicity, operating weeks,…)
Perform gap analysis to identify where present CEBAF performance does not achieve the performance goals
Develop a plan to close the gaps

8. 12GeV NP Program: 2.2 GeV/pass centric
Slide from 2016 C75 review

9. CEBAF 20 year view
A miracle occurs

10. CEBAF Performance Goals

11. Energy Gap and Plan Energy Gap:
Presently CEBAF cannot support design energy (FY17/FY18 operations at 4% below design)
Annual gradient loss exceeds the gain from one C50/year
One C50/year insufficient to maintain energy reach; gap is growing!
Energy Plan:
C75 Upgrade: replace the C20 cavities with high current 5-cell cavities
Re-use as much of the cryomodule as possible
Total cost in terms of MV/$ lower than C50 or C100 options
Upgrade LLRF to digital controls (similar to C100)
Target specifications:
Gradient: 18.5 MV/m
Q0 > 8e9
Upgrade warm region vacuum and clean (SRF quality processing) all warm vacuum regions
two warm girders/year (continues to end of 12GeV/era)
Upgrade analog LLRF with digital LLRF in all zones
two zones per year (continues to end of 12GeV era)

12. Energy Gap and Plan (C75 Upgrades)
Proposed path to design energy (1090 MeV/linac)
Comparable to C50 program post hurricane Isabel
If annual degradation is mitigated: might achieve 1090 MeV/linac by FY21 and with fewer C75 modules

13. Preliminary Performance Plan M&S Cost Estimate
C75s
C100-Refurbs
Preliminary
Near term goal is to close the gaps by FY23
Plan emphasizes improving CEBAF availability/reliability first:
Energy Reach second
Operating at optimal weeks third
All dollar values in FY17 direct costs

14. StayTreat Goals
Are we missing something in regards to CEBAF Availability?
Can we improve the DTM data?
Are we using the DTM data to its fullest potential?
Is the impact on System Availability part of the JLab culture?
Are we ready to implement the CEBAF Performance Plan?
Are we missing something in regards to CEBAF Energy Reach?
What is the root cause of C100 under performance? (This issue is now 3 years old, see 2014 StayTreat)

15. Backup

16. Optimizing 12GeV Operations
Reliability/Availability Focus
4-Hall Operations
Improved Linac/Cryogenic procedures: Reduce risk of cryoplant contamination due to He connections/disconnections
Linac LHe Pressure optimization
Address end-of-life issues:
SRF C20 Warm poly RF windows
SRF C20/C50 end-can O-rings
Improve C100 warm girder tolerance to radiation environment
Identify and correct errant magnets
West Arc to East Arc extension cable, allows for West Arc power supply to power East Arc magnets. Provides CEBAF the ability to support a full ABC program in the event of an East Arc box power supply failure.
Energy Reach/Gradient Maintenance
Linac energy setting: margin -> reliable operations
Identify source of SRF Particulate
Cleaning/processing warm girder regions
Improved tunnel vacuum procedures